Unmanned aerial vehicle, referred to as drone, is an unmanned air vehicle controlled either by a wireless remote control equipment or by its own program control device. The drone was first developed in 1940's, and was used as a target craft in military training at that time. The drone has a wide application, a low cost, and a high cost effectiveness ratio. The drone has no risk of causing human injuries, a strong viability and a great maneuvering performance, and is easy to use. Thus, the drone not only plays an extremely important role in modern warfare, but also has a broad prospect in civilian field. At present, drones are widely used in fields such as guard, urban management, agriculture, geology, meteorology, power, emergency rescue and disaster relief, and video capture.
In the conventional technology, some drones with a fixed wing may have only one rotary wing, and some helicopter type drones may have two or more rotary wings. According to the mechanical features of the rotary wing, each rotary wing rotates to cause ambient airflow to change, thus generating a lift force. Thus, each rotary wing needs to correspond to a certain independent space, in order to create condition for generating the lift force. That is to say, in solutions of the conventional drone, the rotary wing occupies most part of a cross section of the drone, and also causes inconvenience to carrying of the drone.
Therefore, a technical issue to be addressed presently by those skilled in the art is to design a foldable drone, which can be folded up when not in use, to improve the portability of the drone.